This invention relates to a pad which is used to support a utility access conduit in a roadway and to a method for installing such a pad in both new and existing roadways.
There are numerous situations where it is necessary to obtain access to a below-ground utility device. Such access could be to permit a person to enter a pipe, such as with a manhole, to permit a person to actuate a valve, such as with a valve box, or merely to observe a meter or survey monument, such as with a meter box. These situations require that an access conduit be placed in the ground to prevent the device being accessed from becoming covered. In addition, where vehicular or foot traffic will travel over the access conduit, the conduit must be in two telescoping pieces, one which is attached to the object being accessed and the other being supported by the surface. This allows the two pieces to move relative to one another to accommodate movement of the ground due to traffic. A problem with access conduits of this type is that the piece which is supported by the surface will start to move relative to the surface and the bond between them will be broken. This results in degradation of the surface adjacent to the access conduit and displacement of the conduit so that its upper extremity is either above or below the surface, where it will be an impedement to traffic.
A good example of this situation is in the case of a valve box which is installed in an asphalt roadway. When asphalt roads are constructed they are compacted by large rollers to bind the asphalt together. However, these rollers cannot come right up to the edge of a valve box without the risk of striking it and causing it to be damaged. Thus, the asphalt immediately adjacent to the valve box is compacted by hand or by a smaller roller and, as a result, is not as compacted as the asphalt in the rest of the roadway. Traffic on the roadway causes the area around the valve box to further compact which creates a dip in the roadway surface. In addition, since cured asphalt is quite rigid when cold and pliable when hot, traffic striking the valve box causes it to move relative to the roadway, which in time creates a gap between them. Water then enters the gap and freezes, which causes cracking of the roadway adjacent to the valve box. Furthermore, the combination of the valve box being separated from the roadway and the roadway settling can cause the valve box to protrude from the roadway which creates a serious hazard to traffic.
The present invention overcomes the foregoing problems by providing a rectangular block made from rubber or an elastomeric material which is both compressible and resilient which acts as a pad for supporting the access conduit. The pad has an opening through its center which snugly supports the desired utility access conduit. Thus, when the pad is inserted into a roadway surface it provides a relatively large traffic supporting surface which, due to its resiliency, will remain flush with the roadway surface. In addition, due to its compressibility, the pad will move with the access conduit when it is driven over and the access conduit will not become separated from the pad but will continue to be snugly supported by it. As a result, the dip which occurs adjacent to an access conduit in the prior art installations will not occur and water will not be able to seep around the edges of the access conduit where it can cause damage if it becomes frozen.
The pad is embedded into a roadway by first removing a portion of the pavement to make a rectangular hole which is slightly longer and wider than the block and is several inches deeper than the height of the block. The sub-base at the bottom of the hole is leveled and compacted and the hole is partially filled with a settable compound, such as wet concrete mix, so that the distance from the top of the settable compound to the road surface is slightly less than the height of the block. The block, with the access conduit in it, is then placed into the hole and tamped until its top is level with the roadway surface. This will force some of the settable compound into the gap between the block and sides of the hole. The rest of the gap, except for the top one to two inches, is filled with additional set table compound. After the settable compound has cured, the remainder of the gap is filled with a rubber-like sealant.
Accordingly, it is a principal object of the present invention to maintain traffic safety by providing a pad for supporting a utility access conduit in a roadway which will prevent separation of the conduit and the pad and will prevent settling of the roadway surface around the access conduit. It is a further object of the present invention to provide such a pad which can be installed in either a new or existing roadway.
It is a further object of the present invention to provide a method for installing such a pad in an existing roadway.
The foregoing and other objectives, features and advantages of the present invention will be more readily understood upon consideration of the following detailed description of the invention taken in conjunction with the accompanying drawings.